The present invention relates to automatic door closers and more particularly to a structure of a hinge which utilizes the gravity of the door to automatically and retardatively close the door of a house or of a furniture.
Conventional automatic door closer are varied in types. The earliest type of them utilizes a spring or springs to retard the movement of the door. However, it makes a noise. The latest type of them (as shown in FIG. 1) utilizes hydraulic or pneumatic device which comprises a hydraulic or pneumatic tube 10, a shaft 15 having one end pivoted to a door frame 14 and the other end pivoted to a rod 11 which has a free end 12 fixed to a back side of a door 13. When the door 13 is opened, it will be slowly closed without any noise. However, leakage of oil or air may occur after long period of usage and thus will reduce the hydraulic and pneumatic power.
The present invention has a main object to provide a structure of a hinge which utilizes the gravity of a door to retard the closing movement of the door without causing a noise.
Another object of the present invention is to provide a structure of a hinge to automatically and slowly close a door without using an automatic door closer.
Further object of the present invention is to provide a structure of a hinge which is simple, convenient and durable.